Implement sysfs directory that can be used by the users to install data
probes.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/sysfs.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index d5863cc33d230..ccd19fc062f31 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -747,6 +747,35 @@ static const struct kobj_type damon_sysfs_intervals_ktype = {
 	.default_groups = damon_sysfs_intervals_groups,
 };
 
+/*
+ * probes directory
+ */
+
+struct damon_sysfs_probes {
+	struct kobject kobj;
+};
+
+static struct damon_sysfs_probes *damon_sysfs_probes_alloc(void)
+{
+	return kzalloc_obj(struct damon_sysfs_probes);
+}
+
+static void damon_sysfs_probes_release(struct kobject *kobj)
+{
+	kfree(container_of(kobj, struct damon_sysfs_probes, kobj));
+}
+
+static struct attribute *damon_sysfs_probes_attrs[] = {
+	NULL,
+};
+ATTRIBUTE_GROUPS(damon_sysfs_probes);
+
+static const struct kobj_type damon_sysfs_probes_ktype = {
+	.release = damon_sysfs_probes_release,
+	.sysfs_ops = &kobj_sysfs_ops,
+	.default_groups = damon_sysfs_probes_groups,
+};
+
 /*
  * monitoring_attrs directory
  */
@@ -755,6 +784,7 @@ struct damon_sysfs_attrs {
 	struct kobject kobj;
 	struct damon_sysfs_intervals *intervals;
 	struct damon_sysfs_ul_range *nr_regions_range;
+	struct damon_sysfs_probes *probes;
 };
 
 static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
@@ -771,6 +801,7 @@ static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
 {
 	struct damon_sysfs_intervals *intervals;
 	struct damon_sysfs_ul_range *nr_regions_range;
+	struct damon_sysfs_probes *probes;
 	int err;
 
 	intervals = damon_sysfs_intervals_alloc(5000, 100000, 60000000);
@@ -799,8 +830,22 @@ static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
 	if (err)
 		goto put_nr_regions_intervals_out;
 	attrs->nr_regions_range = nr_regions_range;
+
+	probes = damon_sysfs_probes_alloc();
+	if (!probes) {
+		err = -ENOMEM;
+		goto put_nr_regions_intervals_out;
+	}
+	err = kobject_init_and_add(&probes->kobj,
+			&damon_sysfs_probes_ktype, &attrs->kobj, "probes");
+	if (err)
+		goto put_probes_out;
+	attrs->probes = probes;
 	return 0;
 
+put_probes_out:
+	kobject_put(&probes->kobj);
+	attrs->probes = NULL;
 put_nr_regions_intervals_out:
 	kobject_put(&nr_regions_range->kobj);
 	attrs->nr_regions_range = NULL;
@@ -817,6 +862,7 @@ static void damon_sysfs_attrs_rm_dirs(struct damon_sysfs_attrs *attrs)
 	kobject_put(&attrs->nr_regions_range->kobj);
 	damon_sysfs_intervals_rm_dirs(attrs->intervals);
 	kobject_put(&attrs->intervals->kobj);
+	kobject_put(&attrs->probes->kobj);
 }
 
 static void damon_sysfs_attrs_release(struct kobject *kobj)
-- 
2.47.3